Apparatus for reduction of titanium halides and subsequent vacuum separation of reduction products

ABSTRACT

The present invention relates to the art of producing refractory metals, and more particularly to apparatus for magnesium thermoreduction of titanium halides and subsequent vacuum separation of the reduction products. The apparatus proposed herein is characterized by that it is made sectionalized. A middle section thereof hermetically separates the spaces of a reaction chamber and a condenser, and functions as a heat screen. Through said middle section there pass a main channel adapted to communicate the spaces of the reaction chamber and consenser, a drive of a locking means adapted to shut off said main communication channel during the reduction process, communication channels for feeding reactants into the space of the reaction chamber, and a channel for connecting the condenser to an evacuation system, extending to the external surface of the middle section. The apparatus is intended, mainly, for producing titanium sponge.

United States Patent Ivanovich Petrov et al.

APPARATUS FOR REDUCTION OF TITANIUM HALIDES AND SUBSEQUENT VACUUM SEPARATION OF REDUCTION PRODUCTS Inventors: Vasily Ivanovich Petrov, Gavanskaya ulitsa, 10, kv. 2; Boris Nikolaevich Svetlicliny, Kirovsky prospekt, 37b, kv. 6; Jury Alexeevich Demidov, Turbinnaya ulitsa, ll, kv. 96; Nikolai Elin, Nalichnaya ulitsa, 21, kv. 105; Vladimir Petrovich Cherepanov, Suvorovsky prospekt, 56, kv. 89, all of Leningrad; Ivan Nikolaevich Samuilov, ulitsa Novoselov, 3, kv. 18; Ivan Matveevich Cheprmov, ulitsa Novoselov, 6, kv. 16, both of Vostochno-Kazakhstanskaya oblast, Ust-Kamenogorsk, all of USSR.

Filed: Jan. 6, 1971 Appl. No.: 104,230

US. Cl ..266/9, 75/84.5 Int. Cl. ..C22b 53/00 Field of Search ..266/9, 33; 75/84, 84.5

[451 Aug. 15, 1972 [56] References Cited UNITED STATES PATENTS 2,772,875 12/1956 Levy ..266/33 Primary Examiner-Gerald A. Dost AttorneyHolman & Stern ABSTRACT The present invention relates to the art of producing refractory metals, and more particularly to apparatus for magnesium thermoreduction of titanium halides and subsequent vacuum separation of the reduction products.

The apparatus proposed herein is characterized by that it is made sectionalized. A middle section thereof hermetically separates the spaces of a reaction chamber and a condenser, and functions as a heat screen. Through said middle section there pass a main charmel adapted to communicate the spaces of the reaction chamber and consenser, a drive of a locking means adapted to shut ofl said main communication channel during the reduction process, communication channels for feeding reactants into the space of the reaction chamber, and a channel for connecting the condenser to an evacuation system, extending to the external surface of the middle section.

The apparatus is intended, mainly, for producing titanium sponge.

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APPARATUS FOR REDUCTION OF TITANIUM HALIDES AND SUBSEQUENT VACUUM SEPARATION OF REDUCTION PRODUCTS The present invention relates to the art of producing refractory metals, mainly titanium sponge, and more particularly to apparatus for reduction of titanium halides and subsequent vacuum separation of the reduction products.

In the production of titanium sponge a method is widely practized, according to which magnesium thermoreduction of titanium halides is effected in a hermetically sealed reaction chamber, and vacuum separation of the reduction products is effected with the use of a condenser which is installed on the reaction chamber after cooling and dismantling the latter, while for carrying out the process of vacuum separation it being necessary to reheat the reaction chamber up to a temperature of about 980 C.

The cooling and reheating of the reaction chamber, as well as dismantling thereof prior to the installation of the condenser might be obviated when carrying out the processes of reduction and vacuum separation in one apparatus, and this would make the production of titanium sponge less labour-consuming, would diminish the amount of electric power required, and preclude contamination of the reaction mass liable to occur in the course of dismantling the reaction chamber.

However, the creation of an apparatus which would make it possible to carry out the both said operations without dismantling the equipment and without recourse to reheating proves to be a complicated problem.

Attempts have been made to create apparatus of such type, one of these being designed as a retort assembled of two parts. In the lower portion of the retort gas burners are arranged, and the upper portion of the retort is provided with a sluice valve for magnesium, and with communication channels for feeding titanium tetrachloride and for connecting the retort to the evacuation system.

Due to the fact that the operation of reduction takes place in said apparatus within a working space featuring a great temperature difference between the upper and lower portions thereof, the intermediate products of the reaction condense in the retort, including lower titanium chlorides, whereby the yield of the titanium sponge is decreased, and the dismantling of the equipment becomes complicated and hazardous.

Also known in the art is an apparatus comprising a reaction chamber and a condenser whose spaces are separated and communicate through a pipe. Said pipe accommodates a locking means adapted to shut off the pipe in the course of the reduction process. The communication channels for feeding the reactants pass through the cover of the reaction chamber, and the channel for connecting the apparatus to the evacuation system is made in the condenser cover.

In the above-cited apparatus the reaction chamber and the condenser are separated, and the pipe through which they communicate with each other passes through a detachable pipe member which is built into the side walls of the reaction chamber and the condenser; the drive of the locking means adapted to shut off said main communication pipe is disposed inside the condenser and brought out onto the side surface thereof. For carrying out the reduction process, the

reaction chamber is placed into a furnace and covered with a heat screen, through which the pipe members of the main communication pipe and of the communication channel are passed.

Said apparatus suffer from essential structural disadvantages, associated with the arrangement and connection of the apparatus elements. Indeed, in the apparatus of the above-described construction, the inlet of the main communication pipe is disposed in the zone of growth of the garniture titanium sponge and is thus liable to be clogged therewith, so that it becomes necessary to diminish the extent of filling the working space of the reaction chamber. The arrangement of the drive of the locking means inside the condenser results in its being covered with vacuum distillation products. Moreover, such an apparatus is inconvenient for servicing and assembly in view of a great number of connections between its separate elements, which must be hermetically sealed.

It is an object of the present invention to eliminate the above-mentioned disadvantages.

The specific object of the present invention is to provide an apparatus for reduction of titanium halides and for subsequent vacuum separation of the reduction products, wherein the separation of the working spaces of its reaction chamber and condenser would be effected with a minimum number of connections, and the inlets of the main communication channel would be arranged in such a fashion as to preclude their clogging with garniture titanium sponge, the drive of the locking means of the main communication pipe being made so as to preclude condensation of the vacuum separation products thereon.

According to the invention, said specific object is accomplished by that the present apparatus is made sectionalized and comprises a middle section, to which a reaction chamber and a condenser are hermetically connected with their open ends and from the opposite sides. Said middle section of the apparatus hermetically separates the space of the reaction chamber from that of the condenser and serves as a heat screen, passing a main communication pipe or channel which associates the spaces of the reaction chamber and the condenser. The drive of a locking means of the apparatus and the communication channels thereof also pass through said middle section and extend to the external surface thereof.

Such a design ensures the separation of the spaces of the reaction chamber and of the condenser with a minimum number of connections between the elements of the apparatus and makes the apparatus compact, which enhances its reliability in operation, simplifies its servicing, and facilitates the performance of mounting jobs.

It is expedient that the middle section of the apparatus be made partially extending into the condenser, so that the extending portion of the section would make up an annular space with the internal surface of the condenser, with a communication channel extending therefrom, which serves for connecting the apparatus to the evacuation system and passes through the middle section towards the external surface thereof. The width of said annular space should be such as to ensure the formation of a filtering bridge composed of the condensing vacuum separation products between the edge of the extending portion of the middle section and the internal surface of the condenser.

Such an embodiment of the middle section makes the evacuation system convenient for servicing and provides for a reliable operation of the apparatus during the process of vacuum separation.

It is likewise expedient that the reaction chamber and the condenser should be made interchangeable, that is, capable of functioning both in combination with the equipment in which the operation of reducing titanium halides is to be performed, and with that servin g for carrying out vacuum separation of the reduction products.

Such an embodiment of the apparatus will provide for the utilization of the condenser with the vacuum distillation products for carrying out the operation of reduction, and thus for a more complete utilization of the reactants.

The middle section of the apparatus should preferably be made symmetrical to the transverse sectional plane and have a double number of communication channels outgoing from each side of the middle section adjoining the space of the reaction chamber and condenser, each of said communication channels being provided with a plug for shutting off said channels, depending on the process operations being performed in the reaction chamber and condenser.

Such an embodiment of the middle section diminishes the number of mounting jobs required and precludes contact of the condensate with atmospheric air, which results in a higher quality of the titanium sponge produced with the use of the magnesium remaining after the preceding process.

The present invention thus resides in the provision of an apparatus for reduction of titanium halides with subsequent vacuum separation of the reduction products, which ensures a high yield of titanium sponge, is reliable in operation, convenient for servicing and mountmg.

Given hereinbelow is a detailed description of exemplary embodiments of the present invention, to be had in conjunction with the accompanying drawings, wherein:

FIG. 1 shows a longitudinal view of the apparatus of the invention, in which the reaction chamber is disposed in an electric furnace;

FIG. 2 is a longitudinal view of the middle section of the apparatus of the invention, on an enlarged scale;

FIG. 3 is the same (top part-sectioned view);

FIG. 4 is a section taken along IV-IV in FIG. 3;

FIG. 5 shows unit A of FIG. 1 on an enlarged scale;

FIG. 6 is a longitudinal view of the middle section of the apparatus, which, according to the invention, is made symmetrical to the transverse section plane;

FIG. 7 is a top view of the middle section of the apparatus as shown in FIG. 6, combined with a section taken along VII--VII in the same FIG. 6.

Referring now to FIG. I the apparatus of the present invention for reduction of titanium halides and subsequent vacuum separation of the reduction products is made as a sectionalized structure, whose lower section is a reaction chamber 1, and whose upper section is constituted by a condenser 2, with a middle section 3 being disposed therebetween, said middle section 3 interconnecting said reaction chamber 1 and condenser 2 by their open ends.

The reaction chamber is made as a vessel 1 from heat-resistant steel. In the bottom portion of the reaction chamber a tube 4 is fixed for draining off magnesium chloride. The tube 4 may be hermetically closed by a cap 5. At the base of the tube 4 inside the reaction chamber a false bottom 6 is arranged, which serves to preclude the admission of metallic titanium into the locking means of said tube. A flange 7 is welded in the upper portion of the reaction chamber for connecting it to the middle section 3.

When carrying out the technological processes of magnesium thermoreduction of titanium tetrachloride and subsequent vacuum distillation of the titanium sponge obtained in the course of the reduction process, the reaction chamber 1 is placed into an electric furnace 8 provided with heaters disposed in three zones along the furnace height. The body of the furnace 8 is provided with channels 9 for the circulation of cooling air, and with heat sensors 10 to control the temperature of the wall of the reaction chamber. The working space of the furnace is in communication with a vacuum plant through a channel 11. The lower portion of the furnace may be closed tight by means of a cap 12. The channels 9 are associated with a pipe 13 serving to admit cooling air, said pipe 13 having a means 14 for closing thereof, and throttling means 15 for controlling the flow rate of the cooling air.

The condenser 2 is designed similarly to the reaction chamber 1 and likewise comprises a tube 16, a false bottom 18 and a connection flange 18, being thus interchangeable with the reaction chamber; in other words, the condenser 2 and the reaction chamber 1 are of the same shape and the same configuration of parts mating with the other equipment of the apparatus, such as the electric furnace 8, the cooling arrangement and the middle section 3.

The middle section of the apparatus, as can be seen from FIG. 2, is a welded structure with connection flanges l9 and with a main channel 20 in the center thereof, which main channel serves to associate the spaces of the reaction chamber 1 and of the condenser 2 and is shut off by the locking means during the reduction process. According to the invention, the drive of said locking means is brought out through the middle section 3 to the external surface thereof. In the exemplary embodiment under consideration, the main channel 20 is shut off by a valve 21, the latter being associated with a swivel lever 22 which is fixed on a shaft 23 (FIGS. 3 and 4). The shaft 23 is arranged in a supporting tube 24 brought out through the middle section of the apparatus to the external surface thereof, said tube 24 having a cap 25. Through the middle section of the apparatus there pass two pipelines, which serve as communication channels 26 (FIG. 2) and 27 (FIG. 4), the channel 26 serving to feed liquid magnesium, and the channel 27 serving for feeding titanium tetrachloride. Said pipelines are brought out to the extemal surface of the middle section and can be tightly closed with the help of pipe plugs 28 and 29. An annu- Iar chamber 30 is formed in the middle section (FIG. 2 and 4), said chamber 30 being hermetically isolated from the internal spaces of the sections. The annular chamber 30 is made in the upper cylindrical extending portion 31 of the section 3 and through openings 32 associates with the working space of the condenser 2, and through a communication channel 33 (FIGS. 1 and 2) it can be associated with the evacuation system.

The portion 31 of the middle section, which extends into the condenser, makes up with the internal surface of the condenser 2 an annular space 34, to mm wide, which provides for the formation of a filtering layer of the condensate of the vacuum separation products between the edge of the extending portion 31 of the middle section and the internal surface of the condenser.

The middle section is made hermetic, subdivided by annular partitions 35 (FIGS. 2 and 4) into a plurality of spaces which are intercommunicated by openings 36 and constitute the internal space of the section. The annular partitions of the middle section, its bottoms and the internal space function as a heat screen between the working space of the condenser and the working space of the reaction chamber, and also protect the main channel 20 against cooling, so as to preclude condensation of the vacuum distillation of titanium sponge therein.

Gas from the internal space of the middle section is evacuated through a sleeve 37 (FIG. 2). A sleeve 38 passing through the flange of the middle section serves for feeding an inert gas and for measuring the pressure in the reaction chamber.

The reaction chamber and the condenser are associated with each other through the intermediary of the middle section with the help of bolt joints 39 (FIG. 5), a rubber sealing ring 40 being provided between the connection flanges to ensure tightness therebetween. To ensure the protection of the sealing rings against destruction, annular grooves 41 are made in the flanges for feeding cooling water.

Arranged on the flanges 18 of the condenser 2 (FIG. 2) is a cooling means which comprises water boxes 42, a spraying annular collector 43, a water collecting chamber 44, in which water is collected supplied from the annular collector. Cooling water is fed into the water boxes and the annular collector through a distribution manifold 45. The water is drained from the chamber 44 through a sleeve 46. Between the water boxes 42 and the wall of the condenser 2 an air jacket 47 is formed, open from above and communicating with the atmosphere from below through an opening 48 in the chamber 44.

The apparatus of the invention operates as follows.

The apparatus is mounted as shown in FIG. 1. The valve 21 is opened with the help of the drive of the locking means, and the spaces of the reaction chamber 1 and of the condenser 2 are thus brought into communication.

The communication channel 33 is connected to the evacuation system, air is evacuated from the apparatus, and the apparatus is checked for tightness. Through the sleeve 38 (FIG. 2) the apparatus is filled with an inert gas to an excess pressure of 005-02 atm.

The apparatus is installed into the furnace 8 and heated to a temperature of about 800 C, after which the apparatus is charged with a required quantity of liquid magnesium, and the pipe 26 which serves as a channel for feeding liquid magnesium into the apparatus, is closed with the plug 28.

The valve 21 is closed, and through the channel 27 (FIG. 4) titanium tetrachloride is fed at a pre-set rate into the apparatus.

In the apparatus metallic titanium and magnesium chloride are formed according to the reaction 2Mg+TiCl =2 MgCl +Ti.

The reaction being exothermic, the apparatus becomes heated at the level of liquid magnesium. The heating of the upper portion of the apparatus is disconnected, and the reaction zone is blown with cooling air through the channels 9 (FIG. I).

The intensity of blowing is so adjusted that the temperature of the wall of the reaction chamber should be within 780-860 C. Metallic titanium descends to the bottom of the reaction chamber and forms a block of titanium sponge above the false bottom 6. Magnesium chloride sinks to the bottom portion of the apparatus whence it is periodically discharged through the tube 4.

After -65 percent of the magnesium charged have been used in the above-specified reaction, the feeding of titanium tetrachloride is discontinued.

The reduction process is thus finished, and the apparatus is prepared for carrying out vacuum separation of the reduction products.

The vacuum separation process can be carried out with the use of a special furnace, whereinto the hot apparatus is transferred from the furnace in which the reduction process was effected. However, the vacuum separation process can be run likewise in the furnace shown in FIG. 1 and described hereinabove, which is adapted for carrying out the both processes. Following is a description of those operations which are to be performed for preparing the apparatus for carrying out the process of vacuum separation and of the way said vacuum separation is realized with the use of the furnace shown in FIG. 1.

The tube 4 is closed with the cap 5. The furnace 8 is hermetized with the help of the cap 12 and the means 14. The valve 21 is opened, and the spaces of the reaction chamber and of the condenser are brought into communication through the channel 20; the channel 27 (FIG. 4) through which titanium tetrachloride is adapted to be passed is plugged, and the outlet of the shaft 23 is capped; through the communication channel 33 inert gas is evacuated from the interior of the apparatus. Simultaneously gas is evacuated from the interior of the middle section through the sleeve 37 (FIG. 2) and from the interior of the furnace through the channel 11 (FIG. 1), cooling water being also supplied to the external surface of the condenser through the spraying collector 43, and into the water boxes 42.

The process of vacuum separation of the reaction mass is started.

The furnace 8 sets the temperature of the external wall of the reaction chamber about 980 C.

The residual magnesium and magnesium chloride are distilled from the titanium sponge and condense on the internal wall of the condenser 2. The spraying of the external wall ensures the condensation of the sublimates mainly on the condenser wall and partly on the upper surface of the extending portion of the middle section, precluding the penetration of vapors of magnesium and magnesium chloride into the annular space 34, so that a filtering layer of the condensate is formed between the condenser wall and the end face of the extending portion of the section.

Then the end of sublimation of volatile components is determined by any conventional method. The heating of the apparatus is disconnected, the apparatus is filled with an inert gas and withdrawn from the furnace to be cooled down to a temperature close to room temperature, whereupon the apparatus is dismantled.

When using a condenser interchangeable with the reaction chamber, after the apparatus is dismantled, the condenser together with the condensed magnesium remaining therein after the preceding process, is used as a reaction chamber for the subsequent process.

The middle section 3 may be made symmetrical to the transverse section plane, as shown in FIGS. 6 and 7. A circular bushing 49 is arranged in said plane, accommodating a turnable throttle member 50, which is adapted to shut off the main channel communicating the spaces of the condenser 2 and of the reaction chamber ll. Such an embodiment of the middle section features a double number of the communication channels. To diminish the number of pipelines, the channels for feeding titanium tetrachloride and magnesium, outgoing to each side of the middle section adjoining the space of the condenser or the reaction chamber are arranged concentrically in one pipe 51. The communication channels for feeding the reactants can be hermetically closed by a cap 52. The throttle member 50 is fitted on a shaft 53 which extends beyond the side surface of the middle section, where the shaft outlet may be closed with a cap 54.

With such an embodiment of the apparatus, after carrying out the process of vacuum separation of the reduction products, the main communication channel is shut off by the throttle member 50, the condenser 2 together with the middle section 3 is dismantled, the reaction chamber from which the titanium sponge has been removed is attached to the free side of the middle section, and the apparatus is thus made ready again for carrying out a next process of magnesium thermoreduction of titanium halides with the use of the reactants remaining in the condenser after the preceding process of vacuum separation.

Those communication channels which are not required for carrying out the process when the apparatus is in an appropriate position, should be hermetically closed.

The use of the symmetrically embodied middle section with the interchangeable reaction chamber and condenser is conducive to a reduction in the number of mounting operations, eliminates the contact of the condensate with the atmosphere, and thus increases the yield of the titanium sponge with a high quality of the marketable metal.

Though in the disclosure presented hereinabove the producing of titanium sponge has been cited, the present invention can be used to the same advantage in apparatus for carrying out similar processes when producing other refractory metals, for example, zirconium.

What is claimed is:

1. An apparatus for reduction of titanium halides and subsequent vacuum separation of the reduction products, comprising: a reaction chamber; a condenser; a middle section, said reaction chamber and condenser being hermetically connected with their open ends to said middle section from the opposite sides thereof, said middle section hermetically separating the spaces of said reaction chamber and condenser and functioning as a heat screen; a main channel adapted to communicate the spaces of said reaction chamber and condenser and provided in said middle section; a locking means adapted to shut off said main communication channel durin the reduction processa drive of said locking means, rought out through sai middle section to the external surface thereof; communication channels for feeding the reactants into the space of said reaction chamber and for connecting said condenser to an evacuation system, disposed within said middle section and brought out to the external surface thereof.

2. An apparatus as claimed in claim 1, wherein said middle section has a portion that extends into said condenser and forms an annular space with the internal surface thereof, the width of said annular space being so selected as to ensure the formation of a filtering bridge from the condensing products of the vacuum separation process between the edge of the extending portion of said middle section and the internal surface of the condenser.

3. An apparatus as claimed in claim 1, wherein the reaction chamber and the condenser are made interchangeable.

4. An apparatus as claimed in claim 1, wherein the middle section is made symmetrical to the transverse section plane and has a double number of communication channels outgoing from each side of said middle section and provided with plugs for shutting off said communication channels, depending on the operations being carried out in the reaction chamber and condenser. 

2. An apparatus as claimed in claim 1, wherein said middle section has a portion that extends into said condenser and forms an annular space with the internal surface thereof, the width of said annular space being so selected as to ensure the formation of a filtering bridge from the condensing products of the vacuum separation process between the edge of the extending portion of said middle section and the internal surface of the condenser.
 3. An apparatus as claimed in claim 1, wherein the reaction chamber and the condenser are made interchangeable.
 4. An apparatus as claimed in claim 1, wherein the middle section is made symmetrical to the transverse section plane and has a double number of communication channels outgoing from each side of said middle section and provided with plugs for shutting off said communication channels, depending on the operations being carried out in the reaction chamber and condenser. 